The invention relates to a four-stroke internal combustion engine with a rotary-spool valve.
Such an engine is the subject matter of the European Patent EP 0 635 095 B1. The there described rotary-spool valve has the advantage that long valve-open times are achieved, which extend beyond more than 180 crankshaft degrees. Thus, an optimum filling of the combustion chamber during the suction stroke is achieved.
In this four-stroke internal combustion engine it is assumed that a conventionally produced air-fuel mixture is fed to the combustion chamber through the inlet valve. This air-fuel mixture is usually produced by a carburetor.
The French patent FR 26 62 214 describes a two-stroke internal combustion engine with a rotary-spool valve, having a fuel-injection nozzle arranged in a channel between a compressor and the valve shaft. The fuel spray, or jet, of the injection nozzle is directed toward a lead aperture of a valve shaft passage when the passage connects the channel to an opening leading to the combustion chamber. This passage is, however, three-dimensionally curved so that the fuel cannot directly enter into the combustion chamber. Instead the droplets from the fuel jet are carried along by the air compressed by a compressor.
The purpose of this invention is to provide a design for a four-stroke internal combustion engine having a rotary-spool valve of the abovementioned type capable of injecting fuel into the combustion chamber. More specifically, in a four-stroke internal combustion engine with a rotary-spool inlet valve, the cylinder head has a valve shaft supported transversely with respect to the cylinder axis. The valve shaft has a passage extending inclined with respect to the shaft axis and rotates at half of the speed of the crankshaft of the engine. A channel is furthermore provided in the cylinder head that leads to the valve shaft. A fuel-injection nozzle is arranged in the channel so that a jet axis of the nozzle is directed toward an opening provided between the valve shaft and an internal-combustion chamber. The fuel-injection nozzle emits a fuel jet directly into the opening when the opening is openly communicating with the passage.